https://bugs.llvm.org/show_bug.cgi?id=52237
Bug ID: 52237
Summary: Variable's value not available after assignment at Oz
after SROA
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: DebugInfo
Assignee: unassignedb...@nondot.org
Reporter: cristianassaia...@outlook.com
CC: jdevliegh...@apple.com, keith.wal...@arm.com,
llvm-bugs@lists.llvm.org,
paul_robin...@playstation.sony.com
Variable l_201 value is not available after the first loop iteration on lines 4
and 5. It is only available on line 6.
>From bisect, this behavior may be caused by SROA on function (b).
$ cat a.c
short a;
void b() {
char l_201 ;
for (;
a <= 8;
++a) l_201 = 0;
}
int main () {
{
b();
}
}
$ clang -v
clang version 13.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
$ lldb -v
lldb version 13.0.0
$ clang -g -Oz -o opt a.c
$ lldb opt
(lldb) target create "opt"
Current executable set to '/home/stepping/7/reduce/opt' (x86_64).
(lldb) b 4
Breakpoint 1: where = opt`b + 11 at a.c:4:9, address = 0x0000000000400483
(lldb) run
Process 112 launched: '/home/stepping/7/reduce/opt' (x86_64)
Process 112 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000400483 opt`b at a.c:4:9
1 short a;
2 void b() {
3 char l_201 ;
-> 4 for (;
5 a <= 8;
6 ++a) l_201 = 0;
7 }
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x0000000000400485 opt`b at a.c:6:3
3 char l_201 ;
4 for (;
5 a <= 8;
-> 6 ++a) l_201 = 0;
7 }
8 int main () {
9 {
(lldb) frame var
(char) l_201 = '\0'
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x000000000040047f opt`b at a.c:5:5
2 void b() {
3 char l_201 ;
4 for (;
-> 5 a <= 8;
6 ++a) l_201 = 0;
7 }
8 int main () {
(lldb) frame var
(char) l_201 = <variable not available>
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000400483 opt`b at a.c:4:9
1 short a;
2 void b() {
3 char l_201 ;
-> 4 for (;
5 a <= 8;
6 ++a) l_201 = 0;
7 }
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x0000000000400485 opt`b at a.c:6:3
3 char l_201 ;
4 for (;
5 a <= 8;
-> 6 ++a) l_201 = 0;
7 }
8 int main () {
9 {
(lldb) frame var
(char) l_201 = '\0'
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